Characterization of surface topography by confocal microscopy: II. The micro and macro surface irregularities
TL;DR: In this article, the results of the experiments, conducted to measure and assess micro and macro surface irregularities of various machined planar and cylindrical surfaces, using a confocal scanning optical microscope (CSOM) are described.
Abstract: In part I, considering the autofocus and intensity methods of measurement, the principles and performance of a confocal microscope were discussed. In this part, the details of the experiments, conducted to measure and assess micro and macro surface irregularities of various machined planar and cylindrical surfaces, using a confocal scanning optical microscope (CSOM) are described. The three-dimensional surface topographies of various machined planar surfaces and also the form errors, like roundness and cylindricity, are measured and analysed. The significance of the set of new parameters, proposed for characterizing three-dimensional surface roughness and roundness measurements, is indicated. The effect of filtering on the variation in values of three-dimensional surface-topography parameters is studied. The performance of the CSOM is compared with those of conventional stylus and interferometric methods. The system is shown to have a great number of advantages in terms of three-dimensional surface mapping of planar and cylindrical surfaces and recognition of details and analysis for characterization of surfaces.
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TL;DR: The results demonstrate that the increased surface area of the material because of the increasing surface roughness is not the only cause for differences found in the electrochemical behaviour and corrosion resistance of the blasted c.p. Ti.
Abstract: It is well known that the osseointegration of the commercially pure titanium (c.p. Ti) dental implant is improved when the metal is shot blasted in order to increase its surface roughness. This roughness is colonised by bone, which improves implant fixation. However, shot blasting also changes the chemical composition of the implant surface because some shot particles remain adhered on the metal. The c.p. Ti surfaces shot blasted with different materials and sizes of shot particles were tested in order to determine their topographical features (surface roughness, real surface area and the percentage of surface covered by the adhered shot particles) and electrochemical behaviour (open circuit potential, electrochemical impedance spectroscopy and cyclic polarisation). The results demonstrate that the increased surface area of the material because of the increasing surface roughness is not the only cause for differences found in the electrochemical behaviour and corrosion resistance of the blasted c.p. Ti. Among other possible causes, those differences may be attributed to the compressive residual surface stresses induced by shot blasting. All the materials tested have an adequate corrosion and electrochemical behaviour in terms of its possible use as dental implant material.
259 citations
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TL;DR: In this article, Wnt proteins are associated with an osteoblast phenotype, but how Wnt signaling regulates mesenchymal cells differentiation on microstructured titanium (Ti) surfaces is not known.
Abstract: Peri-implant bone formation depends on the ability of mesenchymal cells to colonize the implant surface and differentiate into osteoblasts. Human mesenchymal stem cells (HMSCs) undergo osteoblastic differentiation on microstructured titanium (Ti) surfaces in the absence of exogenous factors, but the mechanisms are unknown. Wnt proteins are associated with an osteoblast phenotype, but how Wnt signaling regulates HMSC differentiation on microstructured Ti surfaces is not known. HMSCs were cultured on tissue culture polystyrene or Ti (PT [Sa = 0.33 μm, θ = 96°], SLA [Sa = 2.5 μm, θ = 132°], modSLA [hydrophilic-SLA]). Expression of calcium-dependent Wnt ligand WNT5A increased and canonical Wnt pathway ligands decreased on microstructured Ti in a time-dependent manner. Treatment of HMSCs with canonical ligand Wnt3a preserved the mesenchymal phenotype on smooth surfaces. Treatment with Wnt5a increased osteoblastic differentiation. Expression of integrins ITGA1, ITGA2, and ITGAV increased over time and correlated with increased WNT5A expression. Treatment of HMSCs with Wnt5a, but not Wnt3a, increased integrin expression. Regulation of integrin expression due to surface roughness and energy was ablated in WNT5A-knockdown HMSCs. This indicates that surface properties regulate stem cell fate and induce osteoblast differentiation via the Wnt calcium-dependent pathway. Wnt5a enhances osteogenesis through a positive feedback with integrins and local factor regulation, particularly though BMP signaling.
127 citations
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TL;DR: In this paper, the theory of optical transfer functions in 3D imaging is presented, with a focus on suitable methods for the establishment of calibration standards for 3D images and surface topography measurements.
Abstract: A significant number of areal surface topography measuring instruments, largely based on optical techniques, are commercially available. However,implementation of optical instrumentation into production is currently difficult dueto the lack of understanding of the complex interaction between the light and the component surface. Studying the optical transfer function of the instrument can help address this issue. Herea review is given of techniques for the measurement of optical transfer functions. Starting from the basis of a spatially coherent, monochromatic confocal scanning imaging system, the theory of optical transfer functions in three-dimensional (3D) imaging is presented. Further generalizations are reviewed allowing the extension of the theory to the description of conventional and interferometric 3D imaging systems. Polychromatic transfer functions and surface topography measurements are also discussed. Following presentation of theoretical results, experimental methods to measure the optical transfer function of each class of system are presented, with a focus on suitable methods for the establishment of calibration standards in 3D imaging and surface topography measurements.
69 citations
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TL;DR: In this article, the effect of the variability in the roughness factor depending on the instrument settings, such as spatial resolution and scan-size, instrument characteristics (voxel dimensions), post-treatment of discrete data array (tessellation algorithm), and the nature of the surface texture (e.g. fractal) was analyzed.
Abstract: Roughness factor is widely used for topography characterization of surfaces. The measurement of meaningful values of roughness factor depends on the instrument settings, e.g. spatial resolution and scan-size, the instrument characteristics (voxel dimensions), the post-treatment of discrete data array (tessellation algorithm), and finally the nature of the surface texture (e.g. fractal). To analyze the influence of all these parameters on the value of roughness factor and evaluate the influence of each parameter, different synthetic (mathematically defined) surfaces and acid-etched/passivated titanium surfaces were used. The titanium surface topographies were studied using two different microscopes: white light confocal microscopy (WLCM) and atomic force microscopy (AFM). In decreasing order of influence, roughness factor values are sensitive to the specific surface nature (fractal or non-fractal), the spatial resolution, the scan-size and the tessellation algorithm, whereas the instrumentation does not seem to be an important parameter in this study. The effect of the variability in the roughness factor depending on the above parameters in interpretation of the Young's contact angle and solid–vapor interfacial energy was studied based on the apparent contact angle observed and the Wenzel's equation. It was found that depending on how roughness factor is measured variations up to 20% in the Young's contact angle or solid–vapor interfacial energy may be found.
63 citations
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TL;DR: In this paper, the authors applied fractal analysis based on power spectral density (PSD) and slit island method (SIM), three-dimensional (3D) surface roughness measurement and surface-topography observations from AFM to form a proper investigative tool which may give a relatively full picture of surface morphology of super fine pulverized coal particles.
Abstract: Super fine pulverized coal combustion is a new pulverized coal combustion technology which has better stability, higher combustion efficiency and lower NOx and SO2 emission than that using conventional particle sizes. In this paper we applied fractal analysis based on power spectral density (PSD) and slit island method (SIM), three-dimensional (3D) surface roughness measurement and surface-topography observations from AFM to form a proper investigative tool which may give a relatively full picture of surface morphology of super fine pulverized coal particles for the first time. The final results indicate that both fractal dimensions calculated by SIM and PSD and roughness of coal particle size increase with the increase of the coal particle size. Besides, the grey relational analysis was used to study the degree of relative importance of the influential factors about the microroughness of coal particle surfaces. The results show that the influence of the coal particle size is the greatest compared with the coal qualities and fractal dimensions. This work provides some reference for a relatively full picture of surface morphology of super fine pulverized coal particles. The findings from this work will be helpful to form the basis and provide guidance for further studies on the chemical and combustion characteristics of super fine pulverized coal particles.
53 citations
References
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01 Jan 1994
TL;DR: Dowson et al. as mentioned in this paper defined surface metrology as "the nature of SURFACES and the signals obtained from them" and defined a set of definitions for surface metroglobalization.
Abstract: Foreword by Professor D. Dowson GENERAL PHILOSOPHY OF MEASUREMENT Where does surface metrology fit in engineering metrology? Importance of surface metrology SURFACE CHARACTERIZATION-THE NATURE OF SURFACES AND THE SIGNALS OBTAINED FROM THEM Surface roughness characterization Waviness Errors of form Comparisons of definitions for surface metrology and coordinate measuring Characterization of defect shapes on the surface PROCESSING Digital methods Digital properties of random surfaces Fourier transform and the FFT Statistical parameters in digital form Properties and implementation of ambiguity function and Wigner distribution function Digital estimation of reference lines for surface metrology Algorithms Transformation in surface metrology Graphical methods Other methods of processing Surface generation INSTRUMENTATION Introduction and historical Measurement systems Optical techniques for measurement of surfaces Capacitance techniques for measurement of surfaces of slopes Inductance techniques Impedance technique-skin effect Other non-standard techniques Electron microscopy Merit of transducers ERRORS, CALIBRATION, TRACEABILITY AND STANDARDIZATION Nature of errors Deterministic or systematic error model Basic components of accuracy evaluation Basic error theory for a system Propagation of errors Some useful statistical tests for surfaces Uncertainty in instruments-calibration in general Calibration of stylus instruments Calibration of form instruments Parameter variation National and international standards Drawing symbols SURFACE METROLOGY IN MANUFACTURE Manufacturing processes Cutting Abrasive processes Unconventional machining Surface roughness produced by machining difficult materials Surface effects other than geometry Surface geometry-a fingerprint of manufacture SURFACE GEOMETRY-ITS IMPORTANCE IN FUNCTION Two body interaction - static effects Functional properties of contact Two body interactions - dynamic effects General roughness and system life One body interactions One body with radiation (optical) Scattering by other waves Systems function SUMMARY AND CONCLUSIONS Characterization and nature of signal Data processing Measurement of trends Calibration Manufacture Function Overview
654 citations
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TL;DR: In this article, surface roughness measurements were performed on a glass-ceramic disk substrate by stylus profiler (SP), atomic force microscope (AFM) and non-contact optical profiler.
Abstract: Surface roughness measurements were performed on a glass-ceramic disk substrate by stylus profiler (SP), atomic force microscope (AFM) and non-contact optical profiler (NOP). Results of surface measurements are presented and the differences between SP, AFM and NOP roughness measurements are discussed. The effects of stylus size, scan size and sampling interval on roughness parameters are investigated. The methodology of choosing the scan size and sampling interval is suggested. AFM is concluded to be the most suitable surface measuring instrument for roughness measurement on the glass-ceramic substrate. If SP is used to make the measurement, the tip radius should be in the order of 0.2 μ. However, localized damage to the test surface may occur owing to high contact stress. NOP using an objective magnification of 40 or lower is not recommended because the glass-ceramic substrate contains submicron roughness.
411 citations
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TL;DR: In this article, the authors discuss different methods that are useful for assessing the errors on the dimensions, form and position of geometric features, and a new approach called the median technique, which gives minimum values of errors is introduced.
Abstract: SUMMARY Measurements are carried out on engineering components and analysed to check the conformity of the components to specification. This paper discusses different methods that are useful for assessing the errors on the dimensions, form and position of geometric features. A new approach called the median technique, which gives minimum values of errors is introduced.
117 citations
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TL;DR: In this paper, reference planes for assessing nominally flat and curved surfaces are recommended through theoretical analysis of algorithms and verification of experimental results from a standardisation point of view, and reference planes are used to assess surfaces in 3D.
Abstract: The objective of this paper is to carry out a comprehensive study of reference planes for surface roughness assessment in 3-D. From a standardisation point of view, reference planes for assessing nominally flat and curved surfaces are recommended through theoretical analysis of algorithms and verification of experimental results.
41 citations
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TL;DR: This paper describes the advantages as well as the range of application of three-dimensional surface roughness analysis, and a number of specially developed software packages perform the data processing.
Abstract: Based on more than a decade's work with digital surface roughness analysis techniques, this paper describes the advantages as well as the range of application of three-dimensional surface roughness analysis. Conventional as well as optical equipment is used for surface mapping, and a number of specially developed software packages perform the data processing, including three-dimensional surface filtering and computation of three-dimensional parameters to describe selected functional aspects of surface topography. Several cases of industrial applications are referred, ranging from seal leakage to die wear and human skin diseases.
36 citations